Drone Lander is an app and you practice flying supply missions to Mars. You begin a descent 5,000 meters above the Mars surface. When you click Start, the supply drone begins falling. (The gravity on Mars is weaker than the gravity on Earth, but there is gravity nonetheless.) The goal is to touch down on the surface with a downward velocity of 5 meters per second or less. Anything faster, and you dig another crater on the surface of Mars. You control the descent by adjusting the throttle, which is represented by a Slider control. More throttle means more thrust and a slower descent rate. Be careful, however. The drone has just enough fuel to arrest your descent and touch down softly if you fly a perfect mission. Use too much throttle too early, and you will run out of fuel and fall the rest of the way to Mars.